What Fincuan is saying is with a zero gyro angle firing solution the ship can be traveling at any speed, when you compute the lead angle you use the target speed to get the correct angle. The higher the speed the bigger the lead angle.

Magic

OK. For some reason with all these aiming things, I have to work it out on paper to understand fully, I can't intuit them, and even just reading about them is hard. I understand the O'Kane method fully, having done all the math.

I appreciate your confusion. He's saying that once you compute the lead angle for a given target, that's all you need to know. Of course it seems a bit silly to say "it doesn't matter the speed" since the lead angle only applies to the result of target motion which is a direct function of its speed.

The speed does matter, but that's what the lead angle computation is for. Assuming your lead angle is still valid you don't have to mess with any TDC dials, including speed, because you've basically done the old TDC-less WWI method instead.

constant bearing attack
 

Playing with the Easy Aob mod, I forgot how simple it is to use the constant bearing attack. I sunk a warship at 3,000 yds, a freighter at 2,000 yds and four torpdoes missed a freighter at 4,000 only because it was the beginning of the war and they ran under its keel, even though I has set them to run at minimum depth. (After they missed, I checked the Attack Map and there were the four torpedoes, dead in the water, floating next the side the freighter they were aimed at.) For those of you about ready to tackle manual targeting, this is a good intermediate step to use with the O'Kane and Cromwell methods. It is extremely accurate, and in one of his above posts, gutted notes he has hit a target at 7,000 yds!

For TMO fans like myself, it is a technique that give your boat a decent chance of avoiding the dds, the scourge of TMO, that have the ability to lock on and track Allied subs at long distances.

Supplement: Just fired 4 shots at a cruiser at 7800 yds using constant bearing technique. I followed them all the way (it took ten minutes for them to run.) They missed by less than half a boat length! The cruiser was veering away from the torpedeos, and must have seen them as it increased its angle of veer as the torpedoes closed. The techique is pretty amazing.